Bashir had the moral high ground in the episode but he was deluding himself not to realize that his actions were guaranteeing his and O'Brien's death. So I'm on O'Brien's side, in this situation he was acting rationally and Bashir was not. There is a time and place for Bashir's attitude in that episode, and it's called The Quickening. And while he may have been technically required in that episode to follow orders from Bashir, O'Brien knew that Bashir would never try to get him court martialed because of their friendship, and additionally I believe Sisko would have situationally sided with O'Brien. The Hippocratic Oath is just to do no harm, it does not force you to medically intervene. There have in fact been cases where Doctors just out with their families off the job have refused to offer medical intervention out of fear of getting sued for malpractice for a broken sternum giving CPR or something.